What does it mean when a cat vibrates its tail? Rattlesnake Tail is one of the signs of the *most* excited happy cats. It can be confused with the behavior of spraying, but in a fixed cat, its actually just an extremely excited cat!!!!! #happycat Why Do Cats Vibrate Their Tails? Reading Your Cat's Body Language Kinship Cat Tail Talk 101 Cat Wisdom 101 Why does my cat shake her tail like this? : r cats